All-sky monitoring and imaging of hard X-rays and gamma-rays

We present a design for a hard X-ray all-sky monitor based on a spherical i mplementation of the coded aperture imaging technique. Use of appropriate d etector elements allows the technique to be tailored to cover an energy ban d from 10 keV to 250 keV. The instrument described can be used as a monitor for a pre-determined list of sources, and is simultaneously able to detect and locate bunts and transient sources anywhere in the sky. We also presen t a derivative of the all-sky monitor design which provides imaging of phot ons up to 10 MeV.